我試圖在java中查詢jena TDB。我的代碼如下。看起來我的TDB數據集是空的,因爲model.size()
(其中model
是數據集默認模型)返回0.我確定它不是空的,因爲我可以用Fuseki用我的sparqlEndpoint查詢它。查詢Jena TDB商店
String directory = "//var//www//fuseki//TDB" ;
Dataset dataset = TDBFactory.createDataset(directory) ;
Model model = dataset.getDefaultModel();
String sparqlQueryString = "SELECT (count(*) AS ?count) { ?s ?p ?o }" ;
Query query = QueryFactory.create(sparqlQueryString) ;
QueryExecution qexec = QueryExecutionFactory.create(query, model);
ResultSet results = qexec.execSelect() ;
ResultSetFormatter.out(results) ;
qexec.close();
System.err.printf("Model size is: %s\n", model.size());
爲什麼'「// var // www // fuseki // TDB」'中的所有雙斜線? –
'System.err.printf(「Model size is:%s \ n」,model.size());'? –